<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>vue3</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
    <div>
        <div id="app">{{ message }}</div>
    </div>
    <script>
        const app = Vue.createApp({
            data() {
                return {
                    message: 'Hello World!'
                }
            }
        })
        app.mount('#app')
    </script>
</body>
</html>